So i let my younger brother play skyrim and he was using the tcl command to basically just fly around and stuff. when i got on afterwards i could no longer sneak or sprint. is that a result of the tcl command or did he do something else to mess it up? and how would i fix it?

Check and see what the default controls are set to.

they all looked normal still but i reset to default just in case. nothing changed.

That seems really odd. TCL shouldn't have anything to do with it..... Key word there being "shouldn't".

Try starting a new game, and see if the controls work on that one.

Can you try to sit in a chair and then stand up and try again. ????